Abstract: An aggregation approach to the incomplete interval reciprocal comparison matrix and the interval complementary comparison matrix is analysed.First,the overall satisfaction membership function of the group decision making is defined based on the allowable error given by the decision-maker respectively.Following that,a weight model is suggested for finding the maximal degree of the group preference satisfaction.Based on the suggested model,the consistency degree of the group preference is defined.Then,an alternation approach is proposed to improve the judgment of the low consistency degree of the decision-maker.Finally,the weight value distributing region model to estimate the group preference is developed to solve the multi-optimization problem and reduce the misleading decision-making owing to the judgment error.The example indicates the effectiveness and practicablity of the approach.